Beam-switching tube counter with transistor amplifier generating carry pulse, dependent on the configuration of the spade electrodes



Nov. 17, 1964 A. SOMLYODY 3,157,815

BEAM-SWITCHING TUBE COUNTER WITH TRANSISTOR AMPLIFIER GENERATING CARRYPULSE, DEPENDENT ON THE CONFIGURATION OF THE SPADE ELECTRODES FiledSept. 24, 1962 ZERO [ SET COUNT PULSE-S FLIP FLOP

INVENTOR ARPAD SOMLYODY ATTORNEY United States Patent This inventionrelates to electronic counting circuits and particularly to countingcircuits using multi-position magnetron beam switching tubes as thecounting elements thereof.

Magnetron beam switching tubes include an electronemitting cathode and aplurality of groups of electrodes,

each of which is adapted to receive an electron beam' from the cathodeand to provide an output signal therefrom. Each group of electrodesincludes a target electrode, from which an output signal is provided andwhich receives the electron beam, a spade electrode which forms andholds an electron beam on its associated target electrode, and aswitching electrode which may be used to switch an electron beam fromone group of electrodes to the next. The spade electrodes may also beutilized to perform this switching function. The tube performs acounting operation as an electronbeam moves from position to positionwithin the tube.

A counting circuit of the type contemplated by the present inventionincludes a plurality of beam switching tubes coupled together to providea plurality of seriesconnected counting stages. As one tube completes acounting operation, a carry pulse is transmitted to the next tube toregister a count therein. In such counters using beam switching tubes,it is customary to couple each counting tube to a carry transistor whichprovides the desired carry pulse at its output or collector electrode.Generally, the output of this transistor is coupled to the drivingcircuit for the next counting tube.

It has been found that the various circuit elements which are thusrequired and which are coupled to the output of the carry transistorrepresent a considerable capacitance adversely affects the speed ofrecovery of the collector electrode after it has performed its functionof generating a carry pulse. Thus, the speed at which each counting tubecan be operated is limited by the ability of the collector electrode ofthe carry transistor to produce a carry pulse when the tube hascompleted its counting cycle. I

In addition, the carry pulse generated by one counting tube and appliedto the next counting tube in a countin chain must be of suificientduration so that it can be properly'registered in said next countingtube. Thus, a balance must be established between the time during whichthe carry transistor is generating a carry pulse and the time duringwhich it is prepared for generating the next carry pulse.

Accordingly, the objects of the present invention are concerned with theprovision of an improved electronic counting circuit using magnetronbeam switching tubes as the counting units thereof and having improvedmeans for controlling the generation of carry pulses.

The present invention is applicable to a counting circuit whichincludes, briefly, a plurality of series-connected pulse each time suchis required.

counting stages, with each stage including a multi-posi tion magnetronbeam switching tube as the counting element thereof. In each countingtube, a selected counting position in the counting cycle is coupledthrough a carry transistor to driving means for the counting tube in thenext counting stage to provide a carry pulse therefor. The carrytransistor provides the desired carry pulse at its collector electrode.The carry transistoris coupled to the counting tube which contols itsoperation in such a manner that (1) it provides a carry pulse of theproper time duration and (2) it is held inoperative for a sufficientlength of time so that it is prepared to provide a carry The inventionis described in detail by reference to the drawing wherein the singlefigure is a schematic representation of a circuit embodying theinvention.

The counting circuit shown and describedis particu larly suited for usewith magnetron beam switching tubes such 'as the type 6700 tube and withsimilar devices sold by Burroughs Corporation and known as BEAM-Xswitches. These devices are cylindrical in form, but they are shown inlinear form as tube 10. The tube 10 has an envelope 12 which contains acentral cathode 14 and ten groups of electrodes numbered 1, 2, 3, 9, 0.Each group of electrodes includes apade electrode in and a targetelectrode 29, and each spade electrode serves to form and hold anelectron beam on its corresponding target electrode which provides anoutput signal from the beam. A switching electrode 22, known as aswitching grid and used for switching an electronbeam from position toposition, is also included in each group of electrodes. In the BEAM-Xswitch, an auxiliary electrode is provided between each target and theadjacent leading spade, and the auxiliary electrode acts as a currentcollecting electrode.

The tube 10 also includes suitable means (not shown) for providing anaxial magnetic field which combines with electric fields within the tubeto form an electron beam and switch it from one group of electrodes tothe next. Such means may be an external permanent magnet or internalmagnets or the like. The direction in which an electron beam is urged,that is clockwise or counter-clockwise, is called theleading direction,and is always the same and is determined by the orientation of theelectric and magnetic fields.

In the circuit shown in the drawing, the cathode 14 of tube it isconnected through a suitable resistor 24 to a source of referencepotential such as ground. The target electrodes 2% are connected, eachto one of the indicator electrodes 28 of a type 6844A indicator tube 36.Thus, visual indication of the counting operation may be provided. Thetargets may also be connected to any other suitable utilization deviceor circuit.

The switching electrodes 22 are" connected in two groups, with theodd-numbered electrodes in one group and the even-numbered electrodes inthe other group. Each group of switching electrodes is connected to oneof the outputs of a flip-flop 34, the input of which is con nected to asuitable source 36 of counting pulses.

According to the invention, the spade electrodes are connected in thefollowing manner. Assuming that a carry pulse is to be transmitted fromtube 10 as an electron beam switches from position 9 to position 0,? theposition 9 is assumed to be the last position in the 3 counting cycle,and position is assumed to be the first position in a new countingcycle. Accordingly, the spade electrodes at positions 0, 1, 2, and 3 areconnected through spade load resistors 38 to a bus 40 which is coupledto a positive DC. power source Vs. The other spade electrodes atpositions 4 through 9 are connected through spade resistors 38 to a bus44.

A carry pulse amplifier, a transistor 50, is provided for transmitting acarry pulse from tube to the next succeeding tube (not shown) in thecounting chain after tube 10 has completed a counting cycle. Because ofthe polarity of the available electrical signals, the carry pulseamplifier is preferably an NPN transistor having base, emitter, andcollector electrodes 51, 52, 53, respectively. The emitter electrode 52is connected through a diode 57, oriented as shown, to the baseelectrode 51 and then through a bias resistor 56 to a positive DC. powersource. The diode 57 maintains the potential level of bus and of emitter52. The emitter electrode is also connected to spade bus 40 through lead66. The base electrode is also connected through lead 64 to spade bus44. The collector electrode 53 is connected through a load resistor 68to the power source Vb and to output terminals 70, from which a carrypulse is derived. The terminals 70 might be coupled to a flip-flop or toany other suitable means for driving the next counting tube.

The circuit shown in the drawing also includes a suitable zerO-setcircuit 80 coupled to the 0 spade for clearing an electron beam in thetube and resetting it at the fO position. A typical zero-set circuitoperates by first reducing the potential of the spade electrodes tocathode potential to clear the tube and then holding the 0 spade at apotential lower than that of the other spades until a beam forms at the0 position. The tube 10 might also be cleared by applying a positivepulse to the cathode .14, and then the beam may be reset at the 0position by the application of a negative pulse to the 0 spade.

In operation ofthe circuit of the invention, it is assumed that thecarry transistor is normally held oif. After an electron beam is formedand set at the 0 position, it is then switched from position to positionby means of flip-flop 34. The transistor 50 is held ed by current flowto its base electrode from the spade electrodes at positions .4 to 9inclusive. When the beam reaches the last or 9 position and thenswitches to the 0 position, current flow from spades 4 to 9 is cut oiland the spade bus 44 rises to a positive potential which is applied tothe base. electrode 51 of the transistor 50. The transistor is turned onthereby. As the transistor turns on, it produces a carry pulse at itsoutput terminal 70.

As the electron beam in tube 10 continues to switch under the influenceof the flip-flop 34, the beam moves through positions 1, 2, and 3,during which time the transistor .50 remains on and the carry pulsepersists. This total time may be of the order of a few microseconds,enough for the next tube to properly utilize the carry pulse. As thebeam moves into position 4 and through positions 4 to 9, current flowsfrom the spade electrodes atthese positions through bus 44 to the baseelectrode 51 of the transistor 50 and keeps the transistor turned. off.During the time that the transistor is thus held oif,,the capacitance ofthe collector electrode 53 and its associated circuitry can be chargedand the collector is raised to the positive potential which it normallycarries when the transistor 59 is ofi. Thus, by the time the electron.beam. again reaches the 9 position, the transistor collector electrodehas completely recovered and is prepared to generate the next carrypulse. If the transistor and its collector were not operated in thisway, the collector could not generate a carry pulse each time the beamcompleted a switching cycle in tube 10.

It can be seen that the circuit of the invention provides means forcontrolling the operation of a pulse carrying 4 circuit between countingtubes and regulating the time during which a carry pulse is availableand the time during which the pulse generating circuitry can recover andprepare itself for generating a carry pulse. It is clear that the timedistributions described above may be varied as required by rearrangingthe spade connections.

What is claimed is:

1. A counter circuit including an electron beam switching tube operableas a counting tube and including a cathode and a plurality of groups ofelectrodes; each group of electrodes including a target electrode whichreceives an electron beam and produces an output signal therefrom, aspade electrode which holds an electron beam on its associated targetelectrode, and a switching electrode which serves to switch an electronbeam from one group of electrodes to the next;

said cathode being coupled to a source of reference potential;

the switching electrode in each group of electrodes being coupled to asource of switching pulses;

the spade electrode in each of a plurality of said groups of electrodesbeing coupled to a first bus;

the spade electrode in each of other of said groups of electrodes beingcoupled to a second bus;

said first and second buses carrying difierent and alternatingpotentials as said tube executes a counting operation;

a transistor having base, emitter, and collector electrodes and providedfor generating a carry pulse from said beam switching tube;

said emitter electrode being coupled to a source of reference potentialand to said first bus;

said collector electrode being coupled to signal input means;

said second bus being coupled to the base electrode of said transistorwhereby said transistor is turned on and olf alternately as thepotential of said second bus changes during the execution of saidcounting operation by said tube;

the length of time during which said transistor is on or off beingdetermined generally by the number of groups of electrodes whose spadeelectrodes are coupled to each bus. r

2. The circuit defined in claim 1 wherein the spade electrodes coupledto said firstbus are in consecutive groups of electrodes and the spadeelectrodes coupled to said second bus are in consecutive groups ofelectrodes.

3. A counter circuit including an electron beam switching tube operableas a counter and having a cathode and a plurality of groups ofelectrodes; each group including a target electrode which receives anelectron beam and produces an output signal therefrom, a spade electrodewhich holds an electron beam on its associated target electrode, and aswitching electrode which serves to switch an electron beam from onegroup of electrodes to the next;

said tube being adapted to execute a counting cycle as an electron beamflows to each of said groups of electrodes in order with one group ofelectrodes being designated as the last group in the counting cycle andthe next being designated as the first in the counting cycle, thearrangement being such that a carry pulse is to be transmitted when anelectron beam switches from said last group to said first p;

said cathode being connected to a source of reference potential;

the switching electrode in each group of electrodes being connected to asource of switching pulses;

the spade electrode in each of said last group of electrodes and of aplurality of groups preceding it in the counting cycle being coupled toa first bus;

the spade electrode in each of the other groups of electrodes includingsaid first group being coupled to a second bus;

said first and second buses carrying diflferent potentials as said tubeexecutes a counting operation with the potentials being effectivelyreversed as one or the other buses receives current from an electronbeam flowing to one of its groups of electrodes;

a transistor having base, emitter, and collector electrodes and providedfor generating a carry pulse from said beam switching tube;

said collector electrode being coupled to an output terminal at which acarry pulse appears;

said first bus being coupled to the base electrode of said transistorwhereby said transistor is turned on 5 and oil alternately as thepotential of said first bus changes during the execution of saidcounting operation by said tube; said second bus being connected to theemitter elec trode of said transistor; the length of time during whichsaid transistor is on or oil being determined generally by the number ofgroups of electrodes whose spade electrodes are coupled to each bus.

No references cited.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,157,815 November 17 1964 Arpad Somlyody d that error appears in theabove numbered pat- It is hereby certifie t the said Letters Patentshould read as ent requiring correction and tha corrected below.

line 43, after "capacitance" insert a This Column 1,

line 23 for "other" read others capacitance column l Signed and sealedthis 6thday of April 1965 (SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. A COUNTER CIRCUIT INCLUDING AN ELECTRON BEAM SWITCHING TUBE OPERABLEAS A COUNTING TUBE AND INCLUDING A CATHODE AND A PLURALITY OF GROUPS OFELECTRODES; EACH GROUP OF ELECTRODES INCLUDING A TARGET ELECTRODE WHICHRECEIVES AN ELECTRON BEAM AND PRODUCES AN OUTPUT SIGNAL THEREFROM, ASPADE ELECTRODE WHICH HOLDS AN ELECTRON BEAM ON ITS ASSOCIATED TARGETELECTRODE, AND A SWITCHING ELECTRODE WHICH SERVES TO SWITCH AN ELECTRONBEAM FROM ONE GROUP OF ELECTRODES TO THE NEXT; SAID CATHODE BEINGCOUPLED TO A SOURCE OF REFERENCE POTENTIAL; THE SWITCHING ELECTRODE INEACH GROUP OF ELECTRODES BEING COUPLED TO A SOURCE OF SWITCHING PULSES;THE SPADE ELECTRODE IN EACH OF A PLURALITY OF SAID GROUPS OF ELECTRODESBEING COUPLED TO A FIRST BUS; THE SPADE ELECTRODE IN EACH OF OTHER OFSAID GROUPS OF ELECTRODES BEING COUPLED TO A SECOND BUS; SAID FIRST ANDSECOND BUSES CARRYING DIFFERENT AND ALTERNATING POTENTIALS AS SAID TUBEEXECUTES A COUNTING OPERATION; A TRANSISTOR HAVING BASE, EMITTER, ANDCOLLECTOR ELECTRODES AND PROVIDED FOR GENERATING A CARRY PULSE FROM SAIDBEAM SWITCHING TUBE; SAID EMITTER ELECTRODE BEING COUPLED TO A SOURCE OFREFERENCE POTENTIAL AND TO SAID FIRST BUS; SAID COLLECTOR ELECTRODEBEING COUPLED TO SIGNAL INPUT MEANS; SAID SECOND BUS BEING COUPLED TOTHE BASE ELECTRODE OF SAID TRANSISTOR WHEREBY SAID TRANSISTOR IS TURNEDON AND OFF ALTERNATELY AS THE POTENTIAL OF SAID SECOND BUS CHANGESDURING THE EXECUTION OF SAID COUNTING OPERATION BY SAID TUBE; THE LENGTHOF TIME DURING WHICH SAID TRANSISTOR IS ON OR OFF BEING DETERMINEDGENERALLY BY THE NUMBER OF GROUPS OF ELECTRODES WHOSE SPADE ELECTRODESARE COUPLED TO EACH BUS.